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comwinapiportable-executable

How to check whether a PE file (DLL,EXE) is a COM component?

I need to write a stub module which, when given a PE (DLL/EXE) as input, will determine whether it is a normal Win32 DLL/EXE or COM DLL/EXE. I need to determine this programatically.

Are there any Windows APIs for this purpose?

Solution

  • I suspect that this is something that would be very hard to do with near 100% accuracy. Some thoughts though:

    • A COM DLL will export functions like DllRegisterServer and DllUnregisterServer. You could use LoadLibrary() to load the Dll, and then GetProcAddress() to check for the presence of these functions. If they're there then its highly likely that its a COM dll.

    • A plain win32 Dll will export DllMain. You could use the same technique to check for that. If you find it then its very likely that its win32.

    • I'm not aware of a way to discover if an exe is a COM server. Servers written using ATL often have a registration script embedded in their resource table, but they don't have to. And you don't need to use ATL to write a COM server. Services using "registry-less com" will similarly have an embedded manifest. You could scan the registry (below HKLM/Classes/Software/) to see if the exe is registered, but it may be that the exe is using registry-less com or just hasn't been regisered yet.

    Hope that helps.